Multicomponent fibers comprising a dissolvable starch component, processes therefor, and fibers therefrom

ABSTRACT

A melt spinnable fiber is provided that comprises a first component comprising a thermoplastic polymer, and a second component comprising thermoplastic starch where the second component is not encompassed by another component or components or if encompassed by another component or components then the second component encompasses a hollow core. A particular use of such a fiber is for removal of the second component in the presence of a solvent in order to produce fibers with desired properties. An agent may be present in the second component for controlling the rate of removal of the second component thereby allowing for physical manipulation of the fiber prior to complete removal of the component. The invention is also directed to nonwoven webs and disposable articles comprising the fibers.

CROSS REFERENCE TO RELATED PATENTS

[0001] This application is a continuation-in-part application and claimspriority to co-pending and commonly owned U.S. applications Ser. Nos.09/853,131 and 09/852,888, both filed May 10, 2001.

FIELD OF THE INVENTION

[0002] The present invention relates to fibers having a diameter of lessthan 200 microns comprising a first component comprising a thermoplasticpolymer and a second component comprising thermoplastic starch whereinthe second component is not encompassed by another component orcomponents or if encompassed by another component or components then thesecond component encompasses a hollow core. Such fibers allow forremoval of the second component by exposure to a solvent for the secondcomponent.

BACKGROUND OF THE INVENTION

[0003] Current woven and nonwoven materials are commonly produced frommulticomponent fibers where one component is removed in order to producefibers with desired diameter or denier, such as in a splittable orislands-in-a-sea configuration for use in synthetic leather, forexample. Many of materials removed are derived from petroleum, mostnotably polyesters or nylons, through treatment processes that are notenvironmentally friendly. These polymeric materials are notbiodegradable and potentially pose a long term problem in waste disposalsystems. There is a need for a removable component in thesemulticomponent fibers that is more environmentally friendly, affordableand that can be made in conjunction with conventional thermoplasticpolymers that can deliver softness at affordable costs.

[0004] Multicomponent fibers that include starch as a component aredesirable since starch is a renewable raw material, of low cost, and isindependent of petroleum products. It is important that fibers havingstarch as a component be processible on standard equipment and useexisting technology.

[0005] The present invention addresses this need for a removable fibercomponent that is environmentally friendly as well as providing goodprocessing characteristics during manufacture.

SUMMARY OF THE INVENTION

[0006] The present invention is directed to melt spinnable fiberscomprising a first component comprising a thermoplastic polymer and asecond component comprising thermoplastic starch wherein the secondcomponent is not encompassed by another component or components or ifencompassed by another component or components then the second componentencompasses a hollow core. Such a configuration allows for the secondcomponent to be removed by exposure to a second-component-removingsolvent.

[0007] The configuration of the multicomponent fibers can besheath-core, islands-in-the-sea, side-by-side, ribbon, segmented pie,for example, or various combination thereof. In a sheath-coreconfiguration, for example, the second component is the sheath, and isremovable by exposure to a second-component-removing solvent. In aconfiguration having a hollow core, the second component may encompassthe hollow core.

[0008] An agent may be present in the second component that affects therate of removal of the second component in the second-component-removingsolvent. Such control of the rate of second component removal allows thefiber to be physically manipulated, such as elongated or formed into afabric, before the component is fully removed. Such a process allows forproduction of fibers with a desired diameter or denier, for example.

[0009] Such compositions are cost-effective and suitable for use incommercially available equipment, while possessing a significant amountof the total composition that is biodegradable, thus eliminatinghazardous and non-environmentally friendly materials from suchprocesses. The present invention is directed toward making durablefibers for a woven, knitted or other suitable fabric making process. Thepresent invention is also directed to nonwoven webs and disposablearticles comprising said fibers.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] These and other features, aspects, and advantages of the presentinvention will become better understood with regard to the followingdescription, appended claims, and accompanying drawings where:

[0011]FIG. 1A-FIG. 1I provide schematic drawings illustratingcross-sectional views of multicomponent fibers.

[0012]FIG. 1A illustrates a typical concentric sheath-coreconfiguration.

[0013]FIG. 1B illustrates a sheath-core configuration with a solid coreand shaped continuous sheath.

[0014]FIG. 1C illustrates a sheath-core configuration with a hollowcore, core x, and continuous sheath y.

[0015]FIG. 1D illustrates a sheath-core configuration with a hollowcore, core x, and shaped continuous sheath y.

[0016]FIG. 1E illustrates a discontinuous sheath-core configuration.

[0017]FIG. 1F illustrates a further discontinuous sheath-coreconfiguration.

[0018]FIG. 1G illustrates a sheath-core configuration with hollow coresurrounded by component X and discontinuous sheath component Y.

[0019]FIG. 1H illustrates a further sheath-core configuration withhollow core surrounded by component X and discontinuous sheath componentY.

[0020]FIG. 1I illustrates an eccentric sheath-core configuration.

[0021]FIG. 2A-FIG. 2B provide schematic drawings illustratingcross-sectional views of bicomponent fibers having a segmented pieconfiguration.

[0022]FIG. 2A illustrates a solid eight segmented pie configuration.

[0023]FIG. 2B illustrates a hollow eight segmented pie configuration.

[0024]FIG. 3 provides a schematic drawing illustrating a cross-sectionalview of a bicomponent fiber having a ribbon configuration.

[0025]FIG. 4 provides schematic drawings illustrating a cross-sectionalview of a bicomponent fiber having a side-by-side configuration.

[0026]FIG. 4A illustrates a side-by-side configuration.

[0027]FIG. 4B illustrates a side-by-side configuration with a roundedadjoining line. The adjoining line is where two components meet.Component Y is present in a higher amount than Component X.

[0028]FIG. 4C illustrates a side-by-side configuration with component Ypositioned on both sides of Component X with a rounded adjoining line.

[0029]FIG. 4D illustrates a side-by-side configuration with component Ypositioned on both sides of Component X.

[0030]FIG. 4E illustrates a shaped side-by-side configuration withcomponent Y positioned on the tips of component X.

[0031]FIG. 5A-FIG. 5C provide schematic drawings illustratingcross-sectional views of multicomponent fibers having anislands-in-the-sea configuration.

[0032]FIG. 5A illustrates a solid islands-in the-sea configuration withcomponent X surrounded by component Y. Component X may be triangular inshape.

[0033]FIG. 5B illustrates a solid islands-in the-sea configuration withcomponent X surrounded by component Y.

[0034]FIG. 5C illustrates a hollow islands-in the-sea configuration withcomponent X surrounded by component Y.

[0035]FIG. 6 provides a schematic drawing illustrating a cross-sectionalview of a tricomponent fiber having a ribbon configuration.

[0036]FIG. 7 provides a schematic drawing illustrating a cross-sectionalview of a tricomponent fiber having a concentric sheath-coreconfiguration with component X comprising the solid core, component Ycomprising the inside continuous sheath, and component Z comprising theoutside continuous sheath.

[0037]FIG. 8 provides a schematic drawing illustrating a cross-sectionalview of a multicomponent fiber having a solid eight segmented pieconfiguration.

[0038]FIG. 9 provides a schematic drawing illustrating a cross-sectionalview of a tricomponent fiber having a solid islands-in-the-seaconfiguration. Component X surrounds a single island of component Y anda plurality of islands of component Z.

DETAILED DESCRIPTION OF THE INVENTION

[0039] All percentages, ratios and proportions used herein are by weightpercent of the composition, unless otherwise specified. All averagevalues are calculated “by weight” of the composition or componentsthereof, unless otherwise expressly indicated. “Average molecularweight”, or “molecular weight” for polymers, unless otherwise indicated,refers to number average molecular weight. Number average molecularweight, unless otherwise specified, is determined by gel permeationchromatography. All patents or other publications cited herein areincorporated herein by reference with respect to all text containedtherein for the purposes for which the reference was cited. Inclusion ofany such patents or publications is not intended to be an admission thatthe cited reference is citable as prior art or that the subject mattertherein is material prior art against the present invention.

[0040] The specification contains a detailed description of (1)materials for the fibers of the present invention, (2) configuration ofthe fibers, (3) material properties of the fiber, (4) processes, and (5)articles.

[0041] (1) Materials

[0042] First Component Material: Thermoplastic Polymers

[0043] Suitable melting temperatures of the thermoplastic polymers arefrom about 60° C. to about 300° C. or, in some embodiments from about80° C. to about 250° C. or from 100° C.-215° C. Thermoplastic polymershaving a melting temperature (Tm) above 250° C. may be used ifplasticizers or diluents or other polymers are used to lower theobserved melting temperature, such that the melting temperature of thecomposition of the thermoplastic polymer-containing component is withinthe above ranges. It may be desired to use a thermoplastic polymerhaving a glass transition (Tg) temperature of less than 0° C. Thethermoplastic polymer component has rheological characteristics suitablefor melt spinning. The molecular weight of the polymer should besufficiently high to enable entanglement between polymer molecules andyet low enough to be melt spinnable. For melt spinning, suitablethermoplastic polymers can have molecular weights about 1,000,000 g/molor below and, in some embodiments from about 5,000 g/mol to about800,000 g/mol, or from about 10,000 g/mol to about 700,000 g/mol or fromabout 20,000 g/mol to about 500,000 g/mol.

[0044] The thermoplastic polymers should be able to solidify fairlyrapidly, preferably under extensional flow, as typically encountered inknown processes for staple fibers (spin draw process), continuousfilaments, or spunbond continuous filament processes, and desirably canform a thermally stable fiber structure. “Thermally stable fiberstructure” as used herein is defined as not exhibiting significantmelting or dimensional change at 25° C. and ambient atmospheric pressureover a period of 24 hours at 50% relative humidity when the fibers areplaced in the environment within five minutes of their formation.Dimensional changes in measured fiber diameter greater than 25%difference, using as a basis the corresponding, original fiber diametermeasurement, would be considered significant. If the original fiber isnot round, the shortest diameter should be used for the calculation. Theshortest diameter should be used for the post-24 hour measurement also.

[0045] Suitable thermoplastic polymers include polyolefins or polyolefincopolymers such as polyethylene or copolymers thereof, including low,high, linear low, or ultra low density polyethylene or copolymerthereof, polypropylene or copolymers thereof, including atacticpolypropylene; polybutylene or copolymers thereof; polyamides orcopolymers thereof, such as Nylon 6, Nylon 11, Nylon 12, Nylon 46, Nylon66; polyesters or copolymers thereof, such as polyethylene terephalates;olefin carboxylic acid copolymers such as ethylene/acrylic acidcopolymer, ethylene/maleic acid copolymer, ethylene/methacrylic acidcopolymer, ethylene/vinyl acetate copolymers or combinations thereof;polyacrylates, polymethacrylates, and their copolymers such aspoly(methyl methacrylates). Other nonlimiting examples of polymersinclude polycarbonates, polyvinyl acetates, poly(oxymethylene), styrenecopolymers, polyacrylates, polymethacrylates, poly(methylmethacrylates), polystyrene/methyl methacrylate copolymers,polyetherimides, polysulfones, or combinations thereof. In someembodiments, thermoplastic polymers include polypropylene, polyethylene,polyamides, polyvinyl alcohol, ethylene vinyl alcohol, ethylene acrylicacid, polyolefin carboxylic acid copolymers, polyesters, andcombinations thereof.

[0046] Biodegradable thermoplastic polymers are also suitable for useherein. Biodegradable materials are susceptible to being assimilated bymicroorganisms such as molds, fungi, and bacteria when the biodegradablematerial is buried in the ground or otherwise comes in contact with themicroorganisms including contact under environmental conditionsconducive to the growth of the microorganisms. Suitable biodegradablepolymers also include those biodegradable materials which areenvironmentally degradable using aerobic or anaerobic digestionprocedures, or by virtue of being exposed to environmental elements suchas sunlight, rain, moisture, wind, temperature, and the like. Thebiodegradable thermoplastic polymers can be used individually or as acombination of biodegradable or non-biodegradable polymers..Biodegradable polymers include polyesters containing aliphaticcomponents. Among the polyesters are ester polycondensates containingaliphatic constituents and poly(hydroxycarboxylic) acid. The esterpolycondensates include diacids/diol aliphatic polyesters such aspolybutylene succinate, polybutylene succinate co-adipate,aliphatic/aromatic polyesters or copolyester such as terpolymers made ofbutylenes diol, adipic acid and terephtalic acid. Thepoly(hydroxycarboxylic) acids include lactic acid based homopolymers andcopolymers, polyhydroxybutyrate (PHB), or other polyhydroxyalkanoatehomopolymers and copolymers. Such polyhydroxyalkanoates includecopolymers of PHB with higher chain length monomers, such as C6-C12, andhigher.

[0047] An example of a suitable commercially available poly lactic acidis NATUREWORKS from Cargill Dow and LACEA from Mitsui Chemical. Anexample of a suitable commercially available diacid/diol aliphaticpolyester is the polybutylene succinate/adipate copolymers sold asBIONOLLE 1000 and BIONOLLE 3000 from the Showa High Polymer Company,Ltd. (Tokyo, Japan). An example of a suitable commercially availablealiphatic/aromatic copolyester is the poly(tetramethyleneadipate-co-terephthalate) sold as EASTAR BIO Copolyester from EastmanChemical or ECOFLEX from BASF.

[0048] The selection of the polymer and amount of polymer will effectthe softness, texture, and properties of the final product as will beunderstood by those or ordinary skill in the art. The thermoplasticpolymer component can contain a single polymer species or a blend of twoor more non-starch thermoplastic polymers. Additionally, other materialscan be present in the thermoplastic polymer component. Typically,thermoplastic polymers are present in an amount of from about 51% to100%, preferably from about 60% to about 95%, more preferably from about70% to about 90%, by total weight of the thermoplastic polymercomponent.

[0049] Second Component Material: Thermoplastic Starch

[0050] The present invention relates to the use of starch, a low costnaturally occurring biopolymer. The starch used in the present inventionis thermoplastic, destructured starch.. The term “destructurized starch”is used to mean starch that is no longer in its naturally occurringgranular structure. The term “thermoplastic starch” or “TPS” is used tomean starch with a plasticizer for improving its thermoplastic flowproperties so that it may be able to be spun into fibers.

[0051] Natural starch does not melt or flow like conventionalthermoplastic polymers. Since natural starch generally has a granularstructure, it needs to be “destructurized”, or “destructured”, before itcan be melt processed and spun like a thermoplastic material. Withoutintending to be bound by theory, the granular structure of starch ischaracterized by granules comprising an structure of discreteamylopectin and amylose regions in a starch granule. This granularstructure is broken down during destructurization, which can be followedby observing a volume expansion of the starch component in the presenceof the solvent or plasticizer. Starch undergoing destructuring in thepresence of the solvent or plasticizer also typically has an increase inviscosity versus non-destructured starch with the solvent orplasticizer. The resulting destructurized starch can be in gelatinizedform or, upon drying and or annealing, in crystalline form, however oncebroken down the natural granular structure of starch will not, ingeneral, return. It is desirable that the starch be fully destructuredsuch that no lumps impacting the fiber spinning process are present. Thedestructuring agent used to destructure the starch may remain with thestarch during further processing, or may be transient, in that it isremoved such that it does not remain in the fiber spun with the starch.

[0052] Starch can be destructured in a variety of different ways. Thestarch can be destructurized with a solvent. For example, starch can bedestructurized by subjecting a mixture of the starch and solvent toheat, which can be under pressurized conditions and shear, to gelatinizethe starch, leading to destructurization. Solvents can also act asplasticizers and may be desirably retained in the composition to performas a plasticizer during later processing. A variety of plasticizingagents that can act as solvents to destructure starch are describedherein. These include the low molecular weight or monomericplasticizers, such as but not limited to hydroxyl-containingplasticizers, including but not limited to the polyols, e.g. polyolssuch as mannitol, sorbitol, and glycerin. Water also can act as asolvent for starch, and can be used to destructurize the starch bydissolving it in water.

[0053] For starch to flow and be melt spinnable like a conventionalthermoplastic polymer, it should have plasticizer present. If thedestructuring agent is removed, it is the nature of the starch to ingeneral remain destructured, however a plasticizer should be added to orotherwise included in the starch component to impart thermoplasticproperties to the starch component in order to facilitate fiberspinning. Thus, the plasticizer present during spinning may be the sameone used to destructure the starch. Alternately, especially when thedestructuring agent is transient as described above, a separate oradditional plasticizer may be added to the starch. Such additionalplasticizer can be added prior to, during, or after the starch isdestructured, as long as it remains in the starch for the fiber spinningstep.

[0054] Suitable naturally occurring starches can include, but are notlimited to, corn starch, potato starch, sweet potato starch, wheatstarch, sago palm starch, tapioca starch, rice starch, soybean starch,arrow root starch, bracken starch, lotus starch, cassava starch, waxymaize starch, high amylose corn starch, and commercial amylose powder.Blends of starch may also be used. Though all starches are usefulherein, the present invention is most commonly practiced with naturalstarches derived from agricultural sources, which offer the advantagesof being abundant in supply, easily replenishable and inexpensive inprice. Naturally occurring starches, particularly corn starch, wheatstarch, potato starch and waxy maize starch, are the preferred starchpolymers of choice due to their economy and availability.

[0055] Modified starch may also be used. Modified starch is defined asnon-substituted, or substituted, starch that has had its nativemolecular weight characteristics changed (i.e. the molecular weight ischanged but no other changes are necessarily made to the starch).Molecular weight can be modified, preferably reduced, by any techniquenumerous of which are well known in the art. These include, for example,chemical modifications of starch by, for example, acid or alkalihydrolysis, acid reduction, oxidative reduction, enzymatic reduction,physical/mechanical degradation (e.g., via the thermomechanical energyinput of the processing equipment), or combinations thereof. Thethermomechanical method and the oxidation method offer an additionaladvantage when carried out in situ. The exact chemical nature of thestarch and molecular weight reduction method is not critical as long asthe average molecular weight is provided at the desired level or range.Such techniques can also reduce molecular weight distribution.

[0056] Natural, unmodified starch generally has a very high averagemolecular weight and a broad molecular weight distribution (e.g. naturalcorn starch has an average molecular weight of up to about 60,000,000grams/mole (g/mol)). It is desirable to reduce the molecular weight ofthe starch for use in the present invention. Molecular weight reductioncan be obtained by any technique known in the art, including thosediscussed above. Ranges of molecular weight for destructured starch orstarch blends added to the melt can be from about 3,000 g/mol to about8,000,000 g/mol, preferably from about 10,000 g/mol to about 5,000,000g/mol, and more preferably from about 20,000 g/mol to about 3,000,000g/mol.

[0057] Optionally, substituted starch can be used. Chemicalmodifications of starch to provide substituted starch include, but arenot limited to, etherification and esterification. For example, methyl,ethyl, or propyl (or larger aliphatic groups) can be substituted ontothe starch using conventional etherification and esterificationtechniques as well known in the art. Such substitution can be done whenthe starch is in natural, granular form or after it has beendestructured. Substitution can reduce the rate of biodegradability ofthe starch, but can also reduce the time, temperature, shear, and/orpressure conditions for destructurization. The degree of substitution ofthe chemically substituted starch is typically, but not necessarily,from about 0.01 to about 3.0, and can also be from about 0.01 to about0.06.

[0058] Typically, the thermoplastic starch comprises from about 51% toabout 100%, preferably from about 60% to about 95%, more preferably fromabout 70% to about 90% by weight of the thermoplastic starch component.The ratio of the starch component to the thermoplastic polymer willdetermine the percent of thermoplastic starch in the bicomponent fibercomponent. The weight of starch in the composition includes starch andits naturally occurring bound water content. The term “bound water”means the water found naturally occurring in starch and before mixing ofstarch with other components to make the composition of the presentinvention. The term “free water” means the water that is added in makingthe composition of the present invention. A person of ordinary skill inthe art would recognize that once the components are mixed in acomposition, water can no longer be distinguished by its origin. Naturalstarch typically has a bound water content of about 5% to about 16% byweight of starch.

[0059] Optional Second Component Material for Controlling the Rate ofStarch Removal

[0060] An agent may be present in the second component in combinationwith the starch that allows control of the rate of starch release andthereby, the amount of starch released when the multicomponent fiber isplaced in a solvent such as water, for example. Examples of such agentsinclude acid substituted vinyl polymers such as ethylene acrylic acidwhich is commercially available as PRIMACOR from Dow Chemical Co.,polyolefin carboxylic acid copolymers such as ethylene acrylic acidcopolymer, ethylene maleic acid copolymer, ethylene methacrylic acidcopolymer, ethylene acrylic acid copolymer, and combinations thereof, apolyhydroxyetherester, a polyhydroxyetheramide such as the BLOX seriesof epoxy-based thermoplastic resins from Dow Chemical Co., and aliphaticor aromatic carboxylic acids or carboxyamides having a meltingtemperature above room temperature (25° C.) and below the upperprocessing temperature of thermoplastic starch of about 300° C. and aminimum boiling point temperature greater than 150° C. Examples includealiphatic saturated or unsaturated C8-C22 carboxylic acids such ascaprylic, oleic, palmitic, stearic, linoleic, linolenic, ricinoleic,erucic acids, or the corresponding fatty acid alcohols or amides of thefatty acids listed above, in particular, mono-,di-, or tri-glycerides ofthe said fatty acids. Examples of suitable aliphatic or aromaticcarboxyamides are stearamide, benzamide, or propionamide, for example.In particular embodiments of the invention, ethylene acrylic acid (EAA),a polyhydroxyetherester (PHEE), a polyhydroxyetheramide (PHEA), or acombination thereof is an agent present in the second component forcontrolling the rate of starch removal.

[0061] Such an agent is present in an amount of about 1% up to 50% byweight of the second component and, in alternative embodiments, 2, 5,10, 15, 20, 25, 30, 35, or 40% of the weight of the second component. Ingeneral, a greater amount of agent slows the rate of starch removal.

[0062] Plasticizer

[0063] One or more plasticizers can be used in the present invention todestructurize the starch and enable the starch to flow, i.e. create athermoplastic starch. As discussed above, a plasticizer may be used as adestructuring agent for starch. That plasticizer may remain in thedestructured starch component to function as a plasticizer for thethermoplastic starch, or may be removed and substituted with a differentplasticizer in the thermoplastic starch component. The plasticizers mayalso improve the flexibility of the final products, which is believed tobe due to the lowering of the glass transition temperature of thecomposition.

[0064] A plasticizer or diluent for the thermoplastic polymer componentmay be present to lower the polymer's melting temperature, modifyflexibility of the final product, or improve overall compatibility withthe thermoplastic starch blend. Furthermore, thermoplastic polymers withhigher melting temperatures may be used if plasticizers or diluents arepresent which suppress the melting temperature of the polymer.

[0065] In general, the plasticizers should be substantially compatiblewith the polymeric components of the present invention with which theyare intermixed. As used herein, the term “substantially compatible”means when heated to a temperature above the softening and/or themelting temperature of the composition, the plasticizer is capable offorming a homogeneous mixture with polymer present in the component inwhich it is intermixed.

[0066] The plasticizers herein can include monomeric compounds andpolymers. The polymeric plasticizers will typically have a molecularweight less than 500,000 g/mol. Polymeric plasticizers can include blockcopolymers and random copolymers, including terpolymers thereof. Incertain embodiments, the plasticizer has a low molecular weightplasticizer, for example a molecular weight of about 20,000 g/mol orless, or about 5,000 g/mol or less, or about 1,000 g/mol or less. Theplasticizers may be used alone or more than one plasticizer may be usedin any particular component of the present invention.

[0067] The plasticizer can be, for example, an organic compound havingat least one hydroxyl group, including polyols having two or morehydroxyls. Nonlimiting examples of useful hydroxyl plasticizers includesugars such as glucose, sucrose, fructose, raffinose, maltodextrose,galactose, xylose, maltose, lactose, mannose erythrose, andpentaerythritol; sugar alcohols such as erythritol, xylitol, malitol,mannitol and sorbitol; polyols such as glycerol (glycerin), ethyleneglycol, propylene glycol, dipropylene glycol, butylene glycol, hexanetriol, and the like, and polymers thereof; and mixtures thereof.Suitable plasticizers especially include glycerine, mannitol, andsorbitol.

[0068] Also useful herein are hydroxyl polymeric plasticizers such aspoloxomers (polyoxyethylene/polyoxypropylene block copolymers) andpoloxamines (polyoxyethylene/polyoxypropylene block copolymers ofethylene diamine). These copolymers are available as PLURONIC® from BASFCorp., Parsippany, N.J. Suitable poloxamers and poloxamines areavailable as SYNPERONIC® from ICI Chemicals, Wilmington, Del., or asTETRONIC® from BASF Corp., Parsippany, N.J. Also suitable for use arehydroxy-containing polymers such as polyvinyl alcohol, ethylene vinylalcohol, and copolymers and blends thereof.

[0069] Also suitable for use herein are hydrogen bond forming organiccompounds, including those which do not have hydroxyl group, includingurea and urea derivatives; anhydrides of sugar alcohols such assorbitan; animal proteins such as gelatin; vegetable proteins such assunflower protein, soybean proteins, cotton seed proteins; and mixturesthereof. Other suitable plasticizers are phthalate esters, dimethyl anddiethylsuccinate and related esters, glycerol triacetate, glycerol monoand diacetates, glycerol mono, di, and tripropionates, butanoates,stearates, lactic acid esters, citric acid esters, adipic acid esters,stearic acid esters, oleic acid esters, and other father acid esterswhich are biodegradable. Aliphatic acids such as ethylene acrylic acid,ethylene maleic acid, butadiene acrylic acid, butadiene maleic acid,propylene acrylic acid, propylene maleic acid, and other hydrocarbonbased acids are further examples of plasticizers.

[0070] When high processing temperature thermoplastic polymers are used,such as with polyamides and polyesters, for example, the starchplasticizer must be carefully chosen so that its vaporizationtemperature is above the processing temperature of the multicomponentfiber. Plasticizers may be blended together to produce vaporizationtemperatures above either one alone, commonly referred to as boilingpoint elevation. A good example of a high boiling point starchplasticizer would be glycerol, which has a vaporization temperature of290° C.

[0071] The amount of plasticizer is dependent upon the molecular weightand amount of starch and the affinity of the plasticizer for the starchor thermoplastic polymer. An amount that effectively plasticizes thestarch can be used. The plasticizer should sufficiently plasticize thestarch component so that it can be processed effectively to form fibers.Generally, the amount of plasticizer increases with increasing molecularweight of starch. Typically, the plasticizer can be present in an amountof from about 2% to about 70%, and can also be from about 5% to about55%, or from about 10% to about 50% of the component into which it isintermixed. A polymer incorporated into the starch component thatfunctions as a plasticizer for the starch shall be counted as part ofthe plasticizer constituent of that component of the present invention.Plasticizer is optional for the thermoplastic polymer components in thepresent invention and can be used at any effective levels, including theranges above, and amounts below 2% are also included.

[0072] Optional Materials

[0073] Optionally, other ingredients may be incorporated into the firstor second component compositions. These optional ingredients may bepresent in quantities of 49% or less, or in alternative embodiments,from about 0.1% to about 30%, or from about 0.1% to about 10% by weightof the component. The optional materials may be used to modify theprocessability and/or to modify physical properties such as elasticity,tensile strength and modulus of the final product. Other benefitsinclude, but are not limited to, stability including oxidativestability, brightness, color, flexibility, resiliency, workability,processing aids, viscosity modifiers, and odor control. Optionalingredients include nucleating agents, salts, slip agents,crystallization accelerators or retarders, odor masking agents,cross-linking agents, emulsifiers, surfactants, cyclodextrins,lubricants, other processing aids, optical brighteners, antioxidants,flame retardants, dyes, pigments, fillers, proteins and their alkalisalts, waxes, tackifying resins, extenders, wet-strength resins, ormixtures thereof Processing aids include magnesium stearate or,particularly in the starch component, ethylene acrylic acid,commercially available from Dow Chemical Co. as PRIMACOR.

[0074] (2) Configuration

[0075] The multiconstituent, multicomponent fibers of the presentinvention may be in several different configurations as long as thesecond component is not encompassed by another component or componentsor if encompassed by another component or components then the secondcomponent encompasses a hollow core. Constituent, as used herein, isdefined as meaning the chemical species of matter or the material.Multiconstituent, as used herein, is defined to mean a fiber orcomponent thereof containing more than one chemical species or material.The fibers will be multicomponent in configuration prior to removal of asecond component. Component, as used herein, is defined as a separatepart of the fiber that has a spatial relationship to another part of thefiber. The term multicomponent, as used herein, is defined as a fiberhaving more than one separate part in spatial relationship to oneanother. The term multicomponent includes bicomponent, which is definedas a fiber having two separate parts in a spatial relationship to oneanother at the exit from the extrusion equipment. The differentcomponents of multicomponent fibers are arranged in substantiallydistinct regions across the cross-section of the fiber and extendcontinuously along the length of the fiber.

[0076] The multicomponent fibers may have two, three, four or morecomponents, as long as the second component is not encompassed byanother component or components or if encompassed by another componentor components then the second component encompasses a hollow core.Accordingly, reference to a first component and a second component isnot meant to exclude other components, unless otherwise expresslyindicated. The drawings provide reference to a component, x, y, z, andw, for example. Components z and w may be third and fourth componentsand may comprise another thermoplastic polymer or thermoplastic blend,for example that provides enhanced physical properties beyond thecombination of a first and second component.

[0077] In one embodiment, the second component comprising thethermoplastic starch surrounds the first component such as in, forexample, a sheath-core configuration where the sheath is the secondcomponent and the core is the first component.

[0078] In a further embodiment, the second component comprising thethermoplastic starch surrounds the first component such as in, forexample, an islands-in-a-sea configuration where the islands are thefirst component and the sea is the second component.

[0079]FIG. 1A-FIG. 9 provide schematic drawings illustratingcross-sectional views of various configurations of multicomponentfibers. A combination of one or more configurations is also an aspect ofthe present invention. A configuration where the second component is notencompassed by another component or components allows the secondcomponent to be exposed to a solvent when the fiber is placed in thesolvent. For example, in FIG. 1A, FIG. 1B, FIG. 1I, FIG. 5A, FIG. 5B,FIG. 5C, the second component is y; in FIG. 1E-FIG. 1H, FIG. 2A, FIG.2B, FIG. 3, FIG. 4A-FIG. 4E, the second component is either x or y; inFIG. 6, the second component is either x, y, or z; in FIG. 7, the secondcomponent is z; in FIG. 8, the second component is wither x, y, z, or w;or in FIG. 9, the second component is x. A configuration where thesecond component is encompassed by another component or components andthe second component encompasses a hollow core also allows the secondcomponent to be exposed to a solvent when the fiber is placed in thesolvent since, in such a configuration, solvent may reach the hollowcore. For example, in FIG. 1C or FIG. 1D, the second component may be xor y. When the second component is x in FIG. 1C or FIG. 1D, solvent hasaccess to the hollow core and starch may be removed from component x bythe solvent.

[0080] The weight ratio of the second component to the first componentcan be from about 5:95 to about 95:5. In alternate embodiments, theratio is from about 10:90 to about 65:35 or from about 15:85 to about50:50.

[0081] The fibers of the present invention may also be splittablefibers. Splitting may occur by a mechanical, thermodynamic, hydrodynamicor chemical means during or after the removal of the second component orby fluid induced distortion.

[0082] A plurality of microfibrils may also result from the presentinvention. The microfibrils are very fine fibers contained within amulti-constituent monocomponent or multicomponent fiber. The pluralityof polymer microfibrils have a cable-like morphological structure andlongitudinally extend within the fiber, which is along the fiber axis.The microfibrils may be continuous or discontinuous. Microfibrils areformed in the present invention as a result of the removal of the secondcomponent in a solvent. The thermoplastic polymer is present in asufficient amount to generate a co-continuous phase morphology such thatthe polymer microfibrils may form. Typically, greater than 15%,preferably from about 15% to about 90%, more preferably from about 25%to about 80%, and more preferably from about 35% to about 70% of polymeris desired in the first component for microfibril formation. A“co-continuous phase morphology” is found when the microfibrils aresubstantially longer than the diameter of the fiber. Microfibrils aretypically from about 0.1 micrometers to about 10 micrometers in diameterwhile the fiber typically has a diameter of from about (10 times themicrofibril) 10 micrometers to about 50 micrometers. In addition to theamount of polymer, the molecular weight of the thermoplastic polymermust be high enough to induce sufficient entanglement to formmicrofibrils. In some embodiments, the molecular weight is from about10,000 to less than 500,000 g/mol.

[0083] The microfibrils may be used in nonwoven articles that aredesired to be extra soft and/or have better barrier properties.

[0084] (3) Material Properties

[0085] The diameter of the fiber of the present invention is less thanabout 200 micrometers (microns), and alternate embodiments can be lessthan about 100 microns, less than about 50 microns, or less than 30microns. In one embodiment hereof, the fibers have a diameter of fromabout 5 microns to about 25 microns. Fiber diameter is controlled byfactors well known in the fiber spinning art including, for example,spinning speed and mass through-put in addition to the process set forthherein.

[0086] The fibers produced in the present invention may beenvironmentally degradable depending upon the amount of starch that ispresent, the polymer used, and the specific configuration of the fiber.“Environmentally degradable” is defined being biodegradable,disintegratable, dispersible, flushable, or compostable or a combinationthereof. In the present invention, the fibers, nonwoven webs, andarticles may be environmentally degradable.

[0087] The fibers described herein are typically used to make disposablenonwoven articles. The articles are commonly flushable. The term“flushable” as used herein refers to materials which are capable ofdissolving, dispersing, disintegrating, and/or decomposing in a septicdisposal system such as a toilet to provide clearance when flushed downthe toilet without clogging the toilet or any other sewage drainagepipe. The fibers and resulting articles may also be aqueous responsive.The term aqueous responsive as used herein means that when placed inwater or flushed, an observable and measurable change will result.Typical observations include noting that the article swells, pullsapart, dissolves, or observing a general weakened structure.

[0088] The fibers of the present invention can have low brittleness andhave high toughness, for example a toughness of about 2 MPa or greater.Toughness is defined as the area under the stress-strain curve.

[0089] Extensibility or elongation is measured by elongation to break.Extensibility or elongation is defined as being capable of elongatingunder an applied force, but not necessarily recovering. Elongation tobreak is measured as the distance the fiber can be stretched untilfailure. It has also been found that the fibers of the present inventioncan be highly extensible.

[0090] The elongation to break of single fibers are tested according toASTM standard D3822 except a strain rate of 200%/min is used. Testing isperformed on an MTS Synergie 400 tensile testing machine with a 10 Nload cell and pneumatic grips. Tests are conducted at a rate of 2inches/minute on samples with a 1-inch gage length. Samples are pulledto break. Peak stress and % elongation at break are recorded andaveraged for 10 specimens.

[0091] Nonwoven products produced from multicomponent fibers can alsoexhibit desirable mechanical properties, particularly, strength,flexibility, softness, and absorbency. Measures of strength include dryand/or wet tensile strength. Flexibility is related to stiffness and canattribute to softness. Softness is generally described as aphysiologically perceived attribute which is related to both flexibilityand texture. Absorbency relates to the products' ability to take upfluids as well as the capacity to retain them.

[0092] (4) Processes

[0093] The first step in producing a multi-component fiber can be acompounding or mixing step. In this compounding step, the raw materialsare heated, typically under shear. The shearing in the presence of heatcan result in a homogeneous melt with proper selection of thecomposition. The melt is then placed in an extruder where fibers areformed. A collection of fibers is combined together using heat,pressure, chemical binder, mechanical entanglement, and combinationsthereof resulting in the formation of a nonwoven web. The nonwoven isthen assembled into an article.

[0094] Compounding

[0095] The objective of the compounding step is to produce a homogeneousmelt composition for each component of the fibers. Preferably, the meltcomposition is homogeneous, meaning that a uniform distribution ofingredients in the melt is present. The resultant melt composition(s)should be essentially free of water to spin fibers. Essentially free isdefined as not creating substantial problems, such as causing bubbles toform which may ultimately break the fiber while spinning. The free watercontent of the melt composition can be about 1% or less, about 0.5% orless, or about 0.15% of less. The total water content includes the boundand free water. Preferably, the total water content (including boundwater and free water) is about 1% or less. To achieve this low watercontent, the starch or polymers may need to be dried before processedand/or a vacuum is applied during processing to remove any free water.The thermoplastic starch, or other components hereof, can be dried atelevated temperatures, such as about 60° C., before spinning. The dryingtemperature is determined by the chemical nature of a component'sconstituents. Therefore, different compositions can use different dryingtemperatures which can range from 20° C. to 150° C. and are, in general,below the melting temperature of the polymer. Drying of the componentsmay be in series or as discrete steps combined with spinning., such asthose known in the art.

[0096] In general, any method known in the art or suitable for thepurposes hereof can be used to combine the ingredients of the componentsof the present invention. Typically such techniques will include heat,mixing, and pressure. The particular order or mixing, temperatures,mixing speeds or time, and equipment can be varied, as will beunderstood by those skilled in the art, however temperature should becontrolled such that the starch does not significantly degrade. Theresulting melt should be homogeneous.

[0097] A suitable method of mixing for a starch and plasticizer blend isas follows:

[0098] 1. The starch is destructured by addition of a plasticizer. Theplasticizer, if solid such as sorbitol or mannitol, can be added withstarch (in powder form) into a twin-screw extruder. Liquids such asglycerine, can be combined with the starch via volumetric displacementpumps.

[0099] 2. The starch is fully destructurized by application of heat andshear in the extruder. The starch and plasticizer mixture is typicallyheated to 120-180° C. over a period of from about 10 seconds to about 15minutes, until the starch gelatinizes.

[0100] 3. A vacuum can applied to the melt in the extruder, typically atleast once, to remove free water. Vacuum can be applied, for example,approximately two-thirds of the way down the extruder length, or at anyother point desired by the operator.

[0101] 4. Alternatively, multiple feed zones can be used for introducingmultiple plasticizers or blends of starch.

[0102] 5. Alternatively, the starch can be premixed with a liquidplasticizer and pumped into the extruder.

[0103] As will be appreciated by one skilled in the art of compounding,numerous variations and alternate methods and conditions can be used fordestructuring the starch and formation of the starch melt including,without limitation, via feed port location and screw extruder profile.

[0104] A suitable mixing device is a multiple mixing zone twin screwextruder with multiple injection points. The multiple injection pointscan be used to add the destructurized starch and the polymer. A twinscrew batch mixer or a single screw extrusion system can also be used.As long as sufficient mixing and heating occurs, the particularequipment used is not critical.

[0105] An alternative method for compounding the materials comprisesadding the plasticizer, starch, and polymer to an extrusion system wherethey are mixed in progressively increasing temperatures. For example, ina twin screw extruder with six heating zones, the first three zones maybe heated to 90°, 120°, and 130° C., and the last three zones will beheated above the melting point of the polymer. This procedure results inminimal thermal degradation of the starch and for the starch to be fullydestructured before intimate mixing with the thermoplastic materials.

[0106] An example of compounding destructured thermoplastic starch wouldbe to use a Werner &Pfleiderer 30 mm diameter 40:1 length to diameterratio co-rotating twin-screw extruder set at 250 RPM with the first twoheat zones set at 50° C. and the remaining five heating zones set 150°C. A vacuum is attached between the penultimate and last heat sectionpulling a vacuum of 10 atm. Starch powder and plasticizer (e.g.,sorbitol) are individually fed into the feed throat at the base of theextruder, for example using mass-loss feeders, at a combined rate of 30lbs/hour (13.6 kg/hour) at a 60/40 weight ratio of starch/plasticizer.Processing aids can be added along with the starch or plasticizer. Forexample, magnesium stearate can be added at a level of 0-1%, by weight,of the thermoplastic starch component.

[0107] Spinning

[0108] The fibers of the present invention can be made by melt spinning.Melt spinning is differentiated from other spinning, such as wet or dryspinning from solution, where in such alternate methods a solvent ispresent in the melt and is eliminated by volatilizing or diffusing itout of the extrudate.

[0109] Spinning temperatures for the melts can range from about 105° C.to about 300° C., and in some embodiments can be from about 130° C. toabout 230° C. The processing temperature is determined by the chemicalnature, molecular weights and concentration of each component.

[0110] In general, high fiber spinning rates are desired for the presentinvention. Fiber spinning speeds of about 10 meters/minute or greatercan be used. In some embodiments hereof, the fiber spinning speed isfrom about 100 to about 7,000 meters/minute, or from about 300 to about3,000 meters/minute, or from about 500 to about 2,000 meters/minute.

[0111] The fiber may be made by fiber spinning processes characterizedby a high draw down ratio. The draw down ratio is defined as the ratioof the fiber at its maximum diameter (which is typically occursimmediately after exiting the capillary of the spinneret in aconventional spinning process) to the final diameter of the formedfiber. The fiber draw down ratio via either staple, spunbond, ormeltblown process will typically be 1.5 or greater, and can be about 5or greater, about 10 or greater, or about 12 or greater.

[0112] Continuous fibers can be produced through, for example, spunbondmethods or meltblowing processes. Alternately, non-continuous (staplefibers) fibers can be produced according to conventional staple fiberprocesses as are well known in the art. The various methods of fibermanufacturing can also be combined to produce a combination technique,as will be understood by those skilled in the art.

[0113] The fibers spun can be collected subsequent for formation usingconventional godet winding systems or through air drag attenuationdevices. If the godet system is used, the fibers can be further orientedthrough post extrusion drawing at temperatures from about 50° to about200° C. The drawn fibers may then be crimped and/or cut to formnon-continuous fibers (staple fibers) used in a carding, airlaid, orfluidlaid process.

[0114] In the process of spinning fibers, particularly as thetemperature is increased above 105° C., typically it is desirable forresidual water levels to be 1%, by weight of the fiber, or less,alternately 0.5% or less, or 0.15% or less to be present in the variouscomponents.

[0115] Bicomponent melt spinning equipment is described in U.S. Pat. No.5,162,074 and is commercially available from, for example, Hills, Inc.located in Melbourne, Fla. USA. Suitable spinnert capillaries for use inspinning to make bicomponent fibers include, for example, capillarieswith a length-to diameter ration of about 4 and a diameter of about 0.35mm, although other capillary dimensions can be used.

[0116] The process of spinning fibers and compounding of the componentscan be done in-line, with compounding, drying and spinning as part of acontinuous process and can be the preferred process execution.

[0117] The residence time of each component in the spinline can havespecial significance when a high melting temperatures thermoplasticpolymer is chosen to be spun with destructured starch. Spinningequipment can be designed to minimize the exposure of the destructuredstarch component to high process temperature by minimizing the time andvolume of destructured starch exposed in the spinneret. For example, thepolymer supply lines to the spinneret can be sealed and separated untilintroduction into the bicomponent pack. Furthermore, one skilled in theart of bicomponent fiber spinning will understand that the at least twocomponents can be introduced and processed in their separate extrudersat different temperatures until introduced into the spinneret.

[0118] For example, consider bicomponent spinning of an islands-in-a-seafiber with a destructured starch sea and polypropylene islands. Thedestructured starch component extruder profile may be 80° C., 150° C.and 150° C. in the first three zones of a three heater zone extruderwith a starch composition similar to B3 of Example 1. The transfer linesand melt pump heater temperatures will also be 150° C. for the starchcomponent. The polypropylene component extruder temperature profilewould be 180° C., 230° C. and 230° C. in the first three zones of athree heater zone extruder. The transfer lines and melt pump are heatedto 230° C. In this case the spinneret temperature can range from 180° C.to 230° C.

[0119] Exposure of Second Component to Second-Component-Removing Solvent

[0120] The second component can be removed by exposure of themulticomponent fiber to a solvent in which the second component isremovable. Most commonly, the solvent is water, however, any solvent inwhich the second component is removed when the fiber is placed in thesolvent is contemplated. A further example of such a solvent isglycerine. The fibers having the starch removed may be used in nonwovenarticles that are desired to be extra soft and/or have better barrierproperties. Additionally, because starch is an inexpensive material, thestarch and polymer fibers with the starch removed will be a morecost-effective fiber.

[0121] The starch component can also be removed by a combinationtechnique where mechanical or hydrodynamic methods can be used to removethe starch in isolation, in series or in combination with a solvent.

[0122] The rate of starch removal can be measured by weight loss of thefibers versus time exposed to solvent for the second component. Thefibers are removed and dried in the oven for 15 minutes at 115° C. Thefibers are then removed from the oven and allowed to cool in an openatmosphere at room temperature for 30 minutes before weighing.

[0123] Physical Manipulation of Fibers

[0124] Fibers are handled during second component removal or aftersecond component removal. Non-limiting examples of handling includethermodynamic annealing, elongation, contraction splitting, and fabricformation.

[0125] An embodiment of the present invention is a process of producinga melt spinnable fiber having a diameter of less than 200 microns, theprocess comprising compounding a first component comprising athermoplastic polymer, compounding a second component comprisingdestructured starch, spinning the first component with the secondcomponent to form a fiber having a diameter of less than 200 microns,wherein the second component is not encompassed by another component orcomponents or if encompassed by another component or components then thesecond component encompasses a hollow core. A further embodiment of theprocess includes contacting the fiber with a solvent for the secondcomponent wherein the second component is removed from the fiber byexposure to the solvent. In another embodiment, the compounding of thesecond component may further include an agent selected from the groupconsisting of an acid substituted vinyl polymer, a polyolefin carboxylicacid copolymer, a polyhydroxyetherester, a polyhydroxyetheramide, aC8-C22 aliphatic saturated or unsaturated carboxylic acid, an aliphaticcarboxyamide, and an aromatic carboxyamide, wherein the second componentis removed from the fiber by exposure to the solvent at a rate that isslower than that of a fiber lacking the agent. A process that furthercomprises physically manipulating the fiber prior to complete removal ofthe second component or after removal of the second component are alsoaspects of the present invention.

[0126] (5) Articles

[0127] The fibers hereof may be used for any purposes for which fibersare conventionally used. This includes, without limitation,incorporation into nonwoven substrates. The fibers hereof may beconverted to nonwovens by any suitable methods known in the art.Continuous fibers can be formed into a web using industry standardspunbond or meltblown type technologies while staple fibers can beformed into a web using industry standard carding, airlaid, or wetlaidtechnologies. Typical bonding methods include: calendar (pressure andheat), thru-air heat, mechanical entanglement, hydrodynamicentanglement, needle punching, and chemical bonding and/or resinbonding. The calendar, thru-air heat, and chemical bonding are thepreferred bonding methods for the starch and polymer multicomponentfibers. Thermally bondable fibers are required for the pressurized heatand thru-air heat bonding methods.

[0128] The fibers of the present invention may also be bonded orcombined with other synthetic or natural fibers to make nonwovenarticles. The synthetic or natural fibers may be blended together in theforming process or used in discrete layers. Suitable synthetic fibersinclude fibers made from polypropylene, polyethylene, polyester,polyacrylates, and copolymers thereof and mixtures thereof. Naturalfibers include cellulosic fibers and derivatives thereof. Suitablecellulosic fibers include those derived from any tree or vegetation,including hardwood fibers, softwood fibers, hemp, and cotton. Alsoincluded are fibers made from processed natural cellulosic resourcessuch as rayon.

[0129] The fibers of the present invention may be used to makenonwovens, among other suitable articles. Nonwoven articles are definedas articles that contains greater than 15% of a plurality of fibers thatare continuous or non-continuous and physically and/or chemicallyattached to one another. The nonwoven may be combined with additionalnonwovens or films to produce a layered product used either by itself oras a component in a complex combination of other materials, such as ababy diaper or feminine care pad. Preferred articles are disposable,nonwoven articles. The resultant products may find use in one of manydifferent uses. Preferred articles of the present invention includedisposable nonwovens for hygiene and medical applications. Hygieneapplications include such items as wipes; diapers, particularly the topsheet or back sheet; and feminine pads or products, particularly the topsheet.

EXAMPLES

[0130] The examples below further illustrate the present invention. Thestarches for use in the examples below are STARDRI 1, STARDRI 100,ETHYLEX 2015, or ETHYLEX 2035, all from Staley Chemical Company. Thelatter Staley materials are substituted starches. The ethylene acrylicacid (EAA) is PRIMACORE 59801 from Dow Chemical. The polypropylene (PP)resin is Basell PROFAX PH-835. The polyethylene (PE) is ASPUN 6811A fromDow Chemical. The poly(L) lactic acid is BIOMER L9000 (Biomer). Thepolyethylene succinate (PES) is BIONOLLE 1020 from Showa High Polymer(Tokyo, Japan). The polyester is F61HC or 9663 from Eastman Chemical.The glycerine is from Dow Chemical Company, Kosher Grade BU OPTIM*Glycerine 99.7%. The sorbitol is from Archer-Daniels-Midland Co. (ADM),Crystalline NF/FCC 177440-2S. Other polymers having similar chemicalcompositions that differ in molecular weight, molecular weightdistribution, and/or comonomer or defect level can also be used.

Example 1

[0131] Thermoplastic starch compositions (TPS'S) are prepared accordingto the following formulations of Table 1. In Table 1, material 1represents starch, material 2 represents a plasticizer, and material 3represents a non-starch thermoplastic polymer. TABLE 1 Composition (byparts) Composition Material 1 Material 2 Material 3 Material 1 Material2 Material 3 B1 Staley ADM sorbitol Dow 60 40 STARDRI 1 PRIMACORE 59801B2 Staley ADM sorbitol Dow 60 40 5 STARDRI 1 PRIMACORE 59801 B3 StaleyADM sorbitol Dow 60 40 10 STARDRI 1 PRIMACORE 59801 B4 Staley ADMsorbitol Dow 60 40 15 STARDRI 1 PRIMACORE 59801 B5 Staley ADM sorbitolDow 60 40 25 STARDRI 1 PRIMACORE 59801 B6 Staley Dow Dow 60 40 STARDRI 1Glycerine PRIMACORE 59801 B7 Staley Dow Dow 60 40 5 STARDRI 1 GlycerinePRIMACORE 59801 B8 Staley Dow Dow 60 40 10 STARDRI 1 Glycerine PRIMACORE59801 B9 Staley Dow Dow 60 40 15 STARDRI 1 Glycerine PRIMACORE 59801 B10Staley Dow Dow 60 40 25 STARDRI 1 Glycerine PRIMACORE 59801 B11 StaleyDow Dow 60 20 STARDRI 1 Glycerine PRIMACORE + + 59801 20 ADM SorbitolB12 Staley Dow Dow 60 20 5 STARDRI 1 Glycerine PRIMACORE + + 59801 20ADM Sorbitol B13 Staley Dow Dow 60 20 25 STARDRI 1 GlycerinePRIMACORE + + 59801 20 ADM Sorbitol B14 Staley ADM sorbitol Dow 70 30 0STARDRI PRIMACORE 59801 B15 Staley ADM sorbitol Dow 70 30 15 STARDRIPRIMACORE 59801 B16 Staley ADM sorbitol Dow 70 30 25 STARDRI PRIMACORE59801 B17 Staley ADM sorbitol Dow 60 40 0 ETHYLEX PRIMACORE 2015 59801B18 Staley ADM sorbitol Dow 60 40 15 ETHYLEX PRIMACORE 2015 59801 B19Staley ADM sorbitol Dow 60 40 0 ETHYLEX PRIMACORE 2035 59801 B20 StaleyADM sorbitol Dow 60 40 15 ETHYLEX PRIMACORE 2035 59801 B21 Staley ADMsorbitol Dow 30 40 0 ETHYLEX PRIMACORE + 2015 + 59801 30 Staley ETHYLEX2035 B22 Staley ADM sorbitol Dow 30 20 0 ETHYLEX + PRIMACORE + + 2015 +Dow 59801 30 20 Staley Glycerine ETHYLEX 2035 B23 Staley ADM sorbitolDow 30 40 15 ETHYLEX PRIMACORE + 2015 + 59801 30 Staley ETHYLEX 2035 B24Staley ADM sorbitol Dow 30 20 0 ETHYLEX + PRIMACORE + + 2015 + Dow 5980130 20 Staley Glycerine ETHYLEX 2035 B25 Staley Dow Dow 60 40 0 ETHYLEXGlycerine PRIMACORE 2015 59801 B26 Staley Dow Dow 60 40 0 ETHYLEXGlycerine PRIMACORE 2035 59801 B27 Staley Dow Dow 60 40 0 ETHYLEXGlycerine PRIMACORE 2015 + 59801 Staley ETHYLEX 2035 B28 Staley Dow Dow60 40 15 ETHYLEX Glycerine PRIMACORE 2015 59801 B29 Staley Dow Dow 60 4015 ETHYLEX Glycerine PRIMACORE 2035 59801

[0132] The above materials can be prepared in a Werner &Pfleiderer 30 mmdiameter 40:1 length to diameter ratio co-rotating twin-screw extruder(although 50mm Baker and Perkins 25:1 and 40:1 twin screw systems havebeen used) set at 250 RPM with the first two heat zones set at 50° C.and the remaining zones to 150° C. A vacuum is attached between thepenultimate and last heat section pulling a vacuum of 10 atm. The starchpowder and sorbitol are individually fed into the feed throat,preferably using mass-loss feeders. Magnesium stearate is preferablyadded also at 0-1 wt %. The glycerine is injected after the first twoheat zones via a heated liquid injection system. The total massthrough-put is typically set to 25 lbs/hour, although rates ranging from5-75 lbs/hour have been used.

[0133] The compounded material is extruded onto an air quench conveyortable and pelletized. Before spinning the TPS compositions, they aretypically dried, if needed after compounding, to moisture levels below 1wt % for the best spinning. The most preferred moisture content is below0.15 wt %.

Example 2

[0134] The TPS composition B1 is melt spun with Basell PROFAX PH-835using an hollow segmented pie bicomponent pattern such as exemplified inFIG. 2B. The melt extrusion temperature is 210° C. The ratio ofcomponents ranges from 10:90 to 50:50. The as-spun filaments are placedin water and the TPS immediately dissolves in room temperature water.

Example 3

[0135] The TPS composition B1 is melt spun with Basell PROFAX PH-835using an islands-in-a-sea bicomponent pattern such as exemplified inFIG. 5A or FIG. 5B where the sea component comprises the TPS. The meltextrusion temperature is 210° C. The ratio of components ranges from30:70 to 80:20. The as-spun filaments are placed in water and the TPSimmediately dissolves in room temperature water.

Example 4

[0136] The TPS composition B1 is melt spun with Basell PROFAX PH-835using a solid sheath/core such as exemplified in FIG. 1A or FIG. 1B witha TPS sheath. The melt extrusion temperature is 210° C. The ratio ofcomponents ranges from 10:90 to 50:50. The as-spun filaments are placedin water and the TPS immediately dissolves in room temperature water.

Example 5

[0137] The TPS composition B4 is melt spun with Basell PROFAX PH-835using an hollow segmented pie bicomponent pattern such as exemplified inFIG. 2B. The melt extrusion temperature is 210° C. The ratio ofcomponents ranges from 10:90 to 50:50. The as-spun filaments are placedin water and the TPS gradually dissolves in room temperature water overabout 15-60 minute time frame. The use of hot water makes it dissolvefaster.

Example 6

[0138] The TPS composition B4 is melt spun with Basell PROFAX PH-835using an islands-in-a-sea bicomponent pattern such as exemplified inFIG. 5A or FIG. 5B where the sea component comprises the TPS. The meltextrusion temperature is 210° C. The ratio of components ranges from30:70 to 80:20. The as-spun filaments are placed in water and the TPSgradually dissolves in room temperature water over about 15-60 minutetime frame. The use of hot water makes it dissolve faster.

Example 7

[0139] The TPS composition B4 is melt spun with Basell PROFAX PH-835using a solid sheath/core such as exemplified in FIG. 1A or FIG. 1B witha TPS sheath. The melt extrusion temperature is 210° C. The ratio ofcomponents ranges from 10:90 to 50:50. The as-spun filaments are placedin water and the TPS gradually dissolves in room temperature water overabout 15-60 minute time frame. The use of hot water makes it dissolvefaster.

Example 8

[0140] The TPS composition B5 is melt spun with Basell PROFAX PH-835using an hollow segmented pie bicomponent pattern such as exemplified inFIG. 2B. The melt extrusion temperature is 210° C. The ratio ofcomponents ranges from 10:90 to 50:50. The as-spun filaments are placedin water and are relatively stable in room temperature water over aperiod of several hours. Over a period of several days they can dissolvein water. The use of boiling water makes it dissolve faster.

Example 9

[0141] The TPS composition B5 is melt spun with Basell PROFAX PH-835using an islands-in-a-sea bicomponent pattern such as exemplified inFIG. 5A or FIG. 5B where the sea component comprises the TPS. The meltextrusion temperature is 210° C. The ratio of components ranges from30:70 to 80:20. The as-spun filaments are placed in water and arerelatively stable in room temperature water over a period of severalhours. Over a period of several days they can dissolve in water. The useof boiling water makes it dissolve faster.

Example 10

[0142] The TPS composition B5 is melt spun with Baseil PROFAX PH-835using a solid sheath/core such as exemplified in FIG. 1A or FIG. 1B witha TPS sheath. The melt extrusion temperature is 210° C. The ratio ofcomponents ranges from 10:90 to 50:50. The as-spun filaments are placedin water and are relatively stable in room temperature water over aperiod of several hours. Over a period of several days they can dissolvein water. The use of boiling water makes it dissolve faster.

Examples 11-30

[0143] Further bicomponent fibers can be produced according to Table 2.TABLE 2 Extrusion Example TPS Ratio Temperature Bicomponent # PolymerComposition Range (° C.) Configuration 11 Basell B1-B22 70:30 to 190-220Islands-in-a- PROFAX PH- 10:90 Sea 835 12 Basell B1-B22 70:30 to 190-220Hollow PROFAX PH- 10:90 Segmented Pie 835 13 Basell B1-B22 70:30 to190-220 Segmented Pie PROFAX PH- 10:90 835 14 Basell B1-B22 90:10 to190-220 Sheath/Core PROFAX PH- 10:90 835 15 Dow ASPUN B1-B22 70:30 to170-200 Islands-in-a- 6811A 10:90 Sea 16 Dow ASPUN B1-B22 70:30 to170-200 Hollow 6811A 10:90 Segmented Pie 17 Dow ASPUN B1-B22 70:30 to170-200 Segmented Pie 6811A 10:90 18 Dow ASPUN B1-B22 90:10 to 170-200Sheath/Core 6811A 10:90 19 PLA B1-B22 70:30 to 190-220 Islands-in-a-10:90 Sea 20 PLA B1-B22 70:30 to 190-220 Hollow 10:90 Segmented Pie 21PLA B1-B22 70:30 to 190-220 Segmented Pie 10:90 22 PLA B1-B22 90:10 to190-220 Sheath/Core 10:90 23 BIONOLLE B1-B22 70:30 to 170-200Islands-in-a- 1020 10:90 Sea 24 BIONOLLE B1-B22 70:30 to 170-200 Hollow1020 10:90 Segmented Pie 25 BIONOLLE B1-B22 70:30 to 170-200 SegmentedPie 1020 10:90 26 BIONOLLE B1-B22 90:10 to 170-200 Sheath/Core 102010:90 27 EASTAR BIO B1-B22 70:30 to 170-200 Islands-in-a 10:90 Sea 28EASTAR BIO B1-B22 70:30 to 170-200 Hollow 10:90 Segmented Pie 29 EASTARBIO B1-B22 70:30 to 170-200 Segmented Pie 10:90 30 EASTAR BIO B1-B2290:10 to 170-200 Sheath/Core 10:90

Examples 31-38

[0144] Still further bicomponent fibers can be produced according toTable 3. TABLE 3 31 F61HC PET B6-B10:B25- 70:30 to 240-280 Islands-in-a-B29 10:90 Sea 32 F61HC PET B6-B10:B25- 70:30 to 240-280 Hollow B29 10:90Segmented Pie 33 F61HC PET B6-B10:B25- 70:30 to 240-280 Segmented PieB29 10:90 34 F61HC PET B6-B10:B25- 90:10 to 240-280 Sheath/Core B2910:90 35 Polyamide 6 B6-B10:B25- 70:30 to 240-280 Islands-in-a- B2910:90 Sea 36 Polyamide 6 B6-B10:B25- 70:30 to 240-280 Hollow B29 10:90Segmented Pie 37 Polyamide 6 B6-B10:B25- 70:30 to 240-280 Segmented PieB29 10:90 38 Polyamide 6 B6-B10:B25- 90:10 to 240-280 Sheath/Core B2910:90

[0145] While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is intended tocover in the appended claims all such changes and modifications that arewithin the scope of the invention.

What is claimed is:
 1. A melt spinnable multicomponent fiber having adiameter of less than 200 microns, comprising: a first componentcomprising a thermoplastic polymer; and a second component comprisingthermoplastic starch, wherein the second component is not encompassed byanother component or components or if encompassed by another componentor components then the second component encompasses a hollow core. 2.The melt spinnable multicomponent fiber of claim 1 wherein the secondcomponent further comprises an agent selected from the group consistingof an acid substituted vinyl polymer, a polyolefin carboxylic acidcopolymer, a polyhydroxyetherester, a polyhydroxyetheramide, a C8-C22aliphatic saturated or unsaturated carboxylic acid, an aliphaticcarboxyamide, and an aromatic carboxyamide.
 3. The melt spinnablemulticomponent fiber of claim 1 wherein the second component comprisesan acid substituted vinyl polymer and the acid substituted vinyl polymeris ethylene acrylic acid.
 4. The melt spinnable multicomponent fiber ofclaim 1 wherein the second component comprises a polyolefin carboxylicacid copolymer and the copolymer is ethylene maleic acid copolymer,ethylene methacrylic acid copolymer, or ethylene acrylic acid copolymer.5. The melt spinnable multicomponent fiber of claim 1 wherein the fiberhas a sheath-core configuration, the first component is in the coreconfiguration and the second component is in the sheath configuration.6. The melt spinnable multicomponent fiber of claim 1 wherein the fiberhas a configuration selected from the group consisting ofislands-in-the-sea, ribbon, segmented pie, side-by-side, and acombination thereof.
 7. The melt spinnable multicomponent fiber of claim1 wherein the thermoplastic polymer is selected from the groupconsisting of polypropylene, polypropylene copolymer, polyethylene,polyethylene copolymer, polyamide, polyvinyl alcohol, ethylene vinylalcohol, polyolefin copolymer, polyolefin carboxylic acid copolymer,polyester, and a combination thereof.
 8. The melt spinnablemulticomponent fiber of claim 1 wherein the thermoplastic polymer isbiodegradable.
 9. The melt spinnable multicomponent fiber of claim 8wherein the biodegradable thermoplastic polymer is selected from a groupconsisting of a crystallizable polylactic acid, a diacid/diol aliphaticpolyester, an aliphatic/aromatic copolyester, a polyhydroxyalkanoate, acopolymer thereof, and a combination thereof.
 10. A melt spinnable fiberhaving a diameter of less than 200 microns, the fiber produced by aprocess comprising: compounding a first component comprising athermoplastic polymer; compounding a second component comprisingdestructured starch; and spinning the first component with the secondcomponent to form a fiber having a diameter of less than 200 microns,wherein the second component is not encompassed by another component orcomponents or if encompassed by another component or components then thesecond component encompasses a hollow core.
 11. A melt spinnable fiberof claim 10 produced by a process further comprising contacting thefiber with a solvent for the second component, wherein the secondcomponent is removed from the fiber by exposure to the solvent.
 12. Themelt spinnable fiber of claim 10 wherein the compounding of the secondcomponent further includes an agent selected from the group consistingof an acid substituted vinyl polymer, a polyolefin carboxylic acidcopolymer, a polyhydroxyetherester, a polyhydroxyetheramide, a C8-C22aliphatic saturated or unsaturated carboxylic acid, an aliphaticcarboxyamide, and an aromatic carboxyamide, and wherein the processfurther comprises contacting the fiber with a solvent for the secondcomponent, wherein the second component is removed from the fiber byexposure to the solvent at a rate that is slower than that of a fiberlacking the agent.
 13. A process of producing a melt spinnable fiberhaving a diameter of less than 200 microns, comprising: compounding afirst component comprising a thermoplastic polymer; compounding a secondcomponent comprising destructured starch; spinning the first componentwith the second component to form a fiber having a diameter of less than200 microns, wherein the second component is not encompassed by anothercomponent or components or if encompassed by another component orcomponents then the second component encompasses a hollow core.
 14. Theprocess of claim 13 further comprising contacting the fiber with asolvent for the second component wherein the second component is removedfrom the fiber by exposure to the solvent.
 15. The process of claim 13wherein the compounding of the second component further includes anagent selected from the group consisting of an acid substituted vinylpolymer, a polyolefin carboxylic acid copolymer, apolyhydroxyetherester, a polyhydroxyetheramide, a C8-C22 aliphaticsaturated or unsaturated carboxylic acid, an aliphatic carboxyamide, andan aromatic carboxyamide, wherein the second component is removed fromthe fiber by exposure to the solvent at a rate that is slower than thatof a fiber lacking the agent.
 16. The process of claim 15 furthercomprising physically manipulating the fiber prior to complete removalof the second component.
 17. A nonwoven web comprising themulticomponent fiber of claim
 1. 18. A disposable article comprising thenonwoven web of claim
 17. 19. A nonwoven web comprising the fiber ofclaim
 12. 20. A disposable article comprising the nonwoven web of claim19.